1. Field of the Invention
The present invention relates generally to surgically implanted gastric bands for encircling the stomach having notches, ribs and/or chambers in the inflatable portion to reduce fatigue or crease fold failure in the device, while increasing the range of adjustment. A method for treating morbid obesity utilizing a fatigue-resistant gastric banding device is also disclosed.
2. Description of the Related Art
A belt-like gastric band for encircling the stomach to control morbid obesity is disclosed by Vincent in U.S. Pat. No. 5,601,604, incorporated herein by reference. The band comprises a belt that can be passed around the stomach and locked into an encircling position in order to create a stoma opening within the stomach. An adjustable portion of the band comprises an inflatable member, which permits fine adjustment of the stoma opening after the stoma is created by locking the band in place. The stoma opening may be adjusted by injecting or withdrawing a fluid into or from an inflatable member. The means for injecting the fluid into the inflatable member usually comprises a fill port located beneath the skin that can be accessed extracorporeally by transdermal injection. Thus, following implantation, the gastric band can be adjusted to enlarge or reduce the stoma as required.
The gastric band is implanted surgically, via open or laparoscopic surgery, which may involve placement of a calibrating apparatus in the stomach to position the stoma and size the pouch created above the stoma. The gastric band is imbricated in position about the stomach to prevent slippage, usually by gastro-gastric sutures (i.e. tissue is wrapped over the band and sutured to itself).
As disclosed by Vincent, the inflatable member or shell is preferably substantially coextensive with an inner stomach-facing surface of the gastric band. Furthermore, it has been observed that the inflatable member should not wrinkle or fold when adjusted, so as to present a substantially smooth contour along the inner circumference. This ensures not only that stomach tissue will not be pinched by the inflatable member, which could lead to discomfort or necrosis, but also protects the shell from a phenomenon known as crease fold failure, which may occur if it is inflated beyond its intended range of adjustment. In the field, it has been observed that silicone or other elastomeric materials commonly used in the manufacture of gastric bands can fatigue or fail if repeatedly compressed, folded, wrinkled, buckled under stress or creased by, for example, over-inflation. This failure mode, which may include abrasion of the opposing surfaces against one another, abrasion of the inner surface of the fold “peak” against the opposing chamber wall, or fatigue of the material at folder intersections (the most highly-stressed areas), is sometimes referred to as crease fold failure.
In some cases, it has also been noted that existing adjustable gastric bands do not provide the overall size or range of adjustment desirable for use in particular patients. For instance, existing gastric bands may be either too large or too small to encircle a patient's stomach, while still allowing for a properly sized stoma. This may be due, for instance, to variations from patient to patient and their individual internal physiologies. Thus, gastric bands are now available in several different sizes, measured according to the circumference of the band (e.g. 9.75 cm, 11 cm, etc.). But due to variations in not only patient physiology, but also in the location and encircling position of the band, the surgical technique used, etc., it may not be evident what size band is necessary until a patient is undergoing surgery. Rather than have a variety of different sizes of gastric bands on hand during the surgical procedure, it would be desirable to have one universal size gastric band available that is adjustable over a wider range than those bands known in the prior art.
If the overall size of the gastric band is increased, the inflatable shell portion may not be capable of being adjusted to form a relatively small stoma without creases, wrinkles or folds forming on the inner stomach-facing surface, which may lead to fatigue or failure of the inflatable member, necessitating additional surgery. It would therefore be desirable to provide a universal size of a fatigue-resistant gastric band having an inflatable member that can be adjusted over a wide range of stoma openings.